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  • Hello. This is 6 Minute English from

  • BBC Learning English. I'm Neil.

  • And I'm Sam.

  • What do shopping with a credit card,

  • finding love through internet

  • dating and waiting for the traffic

  • lights to change have in common?

  • Hmmm, they all involve computers?

  • Good guess, Sam! But how exactly

  • do those computers work?

  • The answer is that they all

  • use algorithms - sets of

  • mathematical instructions

  • which find solutions to problems.

  • Although they are often hidden,

  • algorithms are all around us.

  • From mobile phone maps to

  • home delivery pizza, they

  • play a big part of modern

  • life. And they're the

  • topic of this programme.

  • A simple way to think of

  • algorithms is as recipes.

  • To make pancakes you mix flour,

  • eggs and milk, then melt

  • butter in a frying pan

  • and so on. Computers do

  • this in more a complicated

  • way by repeating mathematical

  • equations over and over again.

  • Equations are mathematical

  • sentences showing how two

  • things are equal. They're

  • similar to algorithms and

  • the most famous scientific

  • equation of all, Einstein's

  • E=MC2, can be thought of as

  • a three-part algorithm.

  • But before my brain gets

  • squashed by all this maths,

  • I have a quiz question for

  • you, Sam. As you know,

  • Einstein's famous equation

  • is E=MC2 - but what does the

  • 'E' stand for? Is it:

  • a) electricity? b) energy?

  • or c) everything?

  • I'm tempted to say 'E' is

  • for 'everything' but I

  • reckon I know the answer:

  • b - 'E' stands for 'energy'.

  • OK, Sam, we'll find out if

  • you're right later

  • in the programme.

  • With all this talk of

  • computers, you might think

  • algorithms are a new idea.

  • In fact, they've been

  • around since Babylonian times,

  • around 4,000 years ago.

  • And their use today can be

  • controversial. Some algorithms

  • used in internet search engines

  • have been accused

  • of racial prejudice.

  • Ramesh Srinivasan is Professor

  • of Information Studies at the

  • University of California.

  • Here's what he said when asked

  • what the word 'algorithm'

  • actually means by BBC World

  • Service's programme, The Forum:

  • My understanding of the term

  • 'algorithm' is that it's not

  • necessarily the bogyman, or

  • its not necessarily something

  • that is, you know, inscrutable

  • or mysterious to all people -

  • it's the set of instructions

  • that you write in some

  • mathematical form or in

  • some software code - so it's

  • the repeated set of

  • instructions that are

  • sequenced, that are used

  • and applied to answer a

  • question or resolve a

  • problem - it's a simple as

  • that, actually.

  • Some think that algorithms

  • have been controversial,

  • but Professor Srinivasan

  • says they are not necessarily

  • the bogyman. The bogyman

  • refers to something people

  • call 'bad' or 'evil' to

  • make other people afraid.

  • Professor Srinivasan thinks

  • algorithms are neither evil

  • nor inscrutable - not

  • showing emotions or thoughts

  • and therefore very difficult

  • to understand.

  • Still, it can be difficult

  • to understand exactly what

  • algorithms are, especially

  • when there are many different

  • types of them. So, let's

  • take an example.

  • It's autumn and we want to

  • collect all the apples from

  • our orchard and divide them

  • into three groups - big, medium

  • and small. One method is to

  • collect all the apples together

  • and compare their sizes.

  • But doing this would take hours!

  • It's much easier to first

  • collect the apples from only

  • one tree - divide those into

  • big, medium or small - and

  • then repeat the process for

  • the other trees, one by one.

  • That's basically what

  • algorithms do - they find

  • the most efficient way to

  • get things done, or in other

  • words, get the best results

  • in the quickest time.

  • Mathematics professor Ian Stewart

  • agrees. Listen as he explains

  • how the algorithm called

  • 'bubble sort' works to BBC

  • World Service's programme,

  • The Forum:

  • Think of when your computer

  • is sorting emails by date and

  • maybe you've got 500 emails

  • and it sorts them by date in

  • a flash. Now it doesn't use

  • bubble sort, but it does

  • use a sorting method and if

  • you tried to do that by

  • hand it would take you a

  • very long time, whatever

  • method you used.

  • Professor Stewart describes

  • how algorithms sort emails.

  • 'To sort' is a verb meaning

  • to group together things

  • which share similarities.

  • Just like grouping the

  • apples by size, sorting

  • hundreds of emails by hand

  • would take a long time.

  • But using algorithms,

  • computers do it in a flash -

  • very quickly or suddenly.

  • That phrase - in a flash -

  • reminds me of

  • how Albert Einstein

  • came up with his famous

  • equation, E=MC2.

  • And that reminds me of your

  • quiz question. You asked

  • about the 'E' in E=MC2.

  • I said it stands for

  • 'energy'. So, was I right?

  • 'Energy' is the correct answer.

  • Energy equals 'M' for mass,

  • multiplied by the Constant

  • 'C' which is the speed

  • of light, squared.

  • OK, let's recap the vocabulary

  • from this programme, starting

  • with 'equation' - a mathematical

  • statement using symbols to

  • show two equal things.

  • If something is called a 'bogyman',

  • it's something considered

  • bad and to be feared.

  • 'Inscrutable' people don't show

  • their emotions so are very

  • difficult to get to know.

  • 'Efficient' means working

  • quickly and effectively

  • in an organised way.

  • The verb 'to sort' means

  • to group together things

  • which share similarities.

  • And finally, if something

  • happens 'in a flash', it

  • happens quickly or suddenly.

  • That's all the time we have

  • to discuss algorithms. And if

  • you're still not 100% sure

  • about exactly what they are,

  • we hope at least you've

  • learned some useful vocabulary!

  • Join us again soon for more

  • trending topics, sensational

  • science and useful vocabulary

  • here at 6 Minute English from

  • BBC Learning English.

  • Bye for now!

  • Goodbye!

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Algorithms - 6 Minute English

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    林宜悉 發佈於 2021 年 12 月 10 日
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